As suggested by the title of the NICHD Strategic Plan, From Cells to Selves, self-understanding represents the pinnacle of individual human development and is a necessary component of the fully functional adult human being. The proposed research identifies a unique and theoretically important, but little examined aspect of early self-understanding, body self-awareness. It aims to define and study developments in young children's objective representations of their own bodies, thereby setting the stage for later inquiry into the correlates and determinants of early body concepts and their sequelae. Formation of a stable, coherent body concept is an important developmental task that lays the foundation for a healthy body image. In adolescents and adults the body image is related to other important aspects of psychosocial functioning, including self-esteem, personal identity, and interpersonal relationships, as well as problems such as obesity and eating disorders. However, the origins of body concepts and early childhood developments in body image and associated risk factors for disordered body concepts are little understood. The proposed studies are built on a conceptual framework that integrates empirical and theoretical literatures across infant development and adult neuropsychology to conceptualize body self-awareness as a distinct component of objective self-awareness, emerging in the second year of life and comprising several potentially dissociable dimensions. Specifically, it is hypothesized that young children develop an objective representation of their own bodies along two separable dimensions: 1) as an object in relation to other objects in the world, with attributes such as height, width, and mass;and 2) as a topographic or spatial representation of their body parts in relation to one another and to the whole. This project will identify the developmental course of each hypothesized dimension of body self-awareness between 18 and 36 months of age in a series of cross-sectional studies, as well relations of each with other indices of developing self-knowledge, including self-recognition and self-reference. Better understanding of early developments in objective self-awareness will contribute to theory and research in multiple aspects of children's social and social-cognitive development. Despite longstanding interest in the development of children's body image and self-understanding, there is very little work concerning its origins and early development. The proposed research aims to increase understanding of the early development of children's objective representations of their own bodies. Formation of a stable, coherent body concept is an important developmental task that lays for the foundation for a healthy body image. With growing evidence of the costs to self-esteem, social functioning, and psychological adjustment of childhood obesity, which is partly mediated by body image, and similar costs of body-image disturbances manifested in disorders like anorexia, knowledge about the developmental roots of the body image is sorely needed.